Air conditioning apparatus



' Nov. 6, 1945. R. J. EISINGER AIR CONDITIONING APPARATUS Filed Feb. 14,1942 CONDITIONED All CCU- OUTSIDE AIR COIL .2 sour: nnnows INDICATEcomma are. 2

DOTI'ED RRRDWS INDICATE HEATI G CYCLI- INVENTOR RUDOLPH J. EISINGERWITNESSES:

ATTOR EY Patented Nov. 6.1945

2,383,314 AIR CONDITIONING APPARATUS Rudolph J. Eisinger, ThornburyTownship. Delaware County,

Pa., asslgnor to Westinghouse Electric Corporation, East Pittsburgh,'Pa., a corporation of Pennsylvania Application February 14, 1942,Serial No. 4 30.841

'1 Claims.

This invention relates to air conditioning apparatus, more particularlyto a reversible cycle refrigerating system for either heating or coolingair for comfort, and it has for an object to provide improved apparatusof the character set forth.

Another object of the invention is to provide heat transfer from therefrigerant in the capillary tube to the suction gas during both cyclesof operation and with the reversing valve disposed within the casing ofthe motor-compressor unit.

Another object is to provide counterflow heat transfer from therefrigerant in the capillary tubes to the suction gas during both cyclesof operation.

The refrigerating system reverses the heating or cooling cycle byreversing the flow of refrigerant through the condenser and theevaporator. The reversing valve is disposed withinthe casing whichencloses the motor compressor unit. The system includes expansion meanscomprising two capillary tubes which connect between thecondenser andthe evaporator and are in heat-transfer relation with the conduitsextending between the reversing valve and the respective heat exchangers(condenser and evaporator). Check valves control the flow through thecapillary tubes and are arranged so as to permit flow oi refrigerantthrough that capillary tube which is in heat-transfer relation to theconduit containing suction gas.

These and other objects are eflected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawing, forming a part of this application, in which:

Fig. 1 is a diagrammatic view of thereversible cycle refrigeratingsystem in accordance with this invention;

Fig. 2 shows an alternate. arrangement of the heat exchangers andcapillary tubes; and,

Fig. 3 is a sectional view of a reversing valve which may be employed. I

Referring to the drawing for a detail description of the invention, inFig. 1 is shown a reversible cycle refrigerating system including twoheat exchangers l and H which may be of the conventional cross-finnedserpentine coiled type.

Provision is made for conveying air over the 0011 I0 and delivering thesame to the enclosure to be air conditioned. The col] ill serves as theevaporator during the cooling cycle and as the condenser during theheating cycle. Provision is also made for conveying outside air over thecoil ii and discharging the same to outdoors or other place exterior ofthe enclosure. The coil ll serves as the condenser during the coolingcycle and as the evaporator during the heating cycle. The runs or tubesof each coil are preferably connected to provide a refrigerantpath-extending from the top through the successively lower adjacent runsto the bottom of the coil so that when the coil is serving as thecondenser the condensed refrigerant flows by gravity to the bottom ofthe coil.

The refrigerating system further includes a motor compressor "nit l3which comprises a compressor l4 and a motor I5 directly connected to thecompressor for driving the same. The compressor and the motor areenclosed within a hermetically-sealed or fluld-tight casing IS. Thecompressor draws refrigerant gas from the interior of the casing l6, thegas being drawn through the motor for the purpose of cooling the sameand then conveyed through a conduit ll to the compressor. The compressedgas is conveyed from the compressor through a discharge conduit l8 to areversing valve IS. A reservoir or accumulator 2| is provided in thepath of the suction gas to separate out and to retain liquid refrigerantfrom the suction gas returning from the evaporator. The accumulator 2|is disposed within the casing I6 and its inlet is connected to thereversing valve I9 by a conduit '22. Refrigerant gas is discharged fromthe top of the accumulator directly into the interior of the casing l6while the liquid refrigerant is retained therein. The reversing valve I9is connected to the upper ends of the coils in and by means of conduits23 and 24.

The reversing valve I9 is adapted to place the compressor suction anddischarge in communication with the coils I0 and II, respectively, andto reverse the connections and place them in communication with thecoils ii and I0, respectively. While any suitable construction ofreversing valve may be used so far as the present invention isconcerned, it is preferred to use the one which is shown in Fig. 3 andwhich will be readily apparent from the drawing. This valve involves theinvention of John G. Ritter, claimed in his application Serial No.377,410, filed February 5, 1941. It includes a casing 25 made in threeparts and an axially-movable valve member 26 having annular ribs or lips21 and 28 which extend into annular recesses 29 and 30 communicatingwith the conduits 23 and 24, respectively. The discharge conduit l8communicates with the interior of the casing 25 intermediate therecesses 29 and 30 while the conduit 22 communicates with the right-handend of the interior of the casing and also with the left-hand 'endthrough a passage formed in the valve member 26. When the valve member26 is moved to the right so that the ribs 21 and 28 seat against theright-hand sides of the recesses 29 and 30, as shown in Fig. 3, the

with the conduit 24.

Suitable provision is made for actuating the reversing valve l9. Inaccordance with the invention or E. R. Wolfert, as disclosed in hiscopending application Serial No. 400,162, filed June 28, 1941, thereversing valve I9 is actuated by and ln'accordance with the directionof rotation of the shaft 20 of the motor compressor unit. By using asingle phase compressor motor the direction of rotation may be readilyreversed by connecting the compressor winding to one side or the otherof the electrical supply conductors. This is illustrated in Fig. 1wherein the double-throw switch 3| is adapted to place the circuit ofthe capacitor winding, which includes the capacitor 32, to either theline conductor L| or L2. When the capacitor-circuit is connected to theconductor Ll, the shaft 20 rotates in counterclockwise direction, asseen'in Fig. l, and when it is connected to the conductor L2 the shaft20 rotates in clockwise direction. A switch 33 may be provided in theline conductor L| to interrupt the supply of current to the motor.

The mechanism for actuating the reversing valve l9 includes a sleeve 34which encircles the shaft 20 and which is dragged by the shaft when itis free to rotate. However, it is adapted to slip relative to the shaft.When the shaft 20 rotates in counterclockwise direction, the sleeve 34moves the movable valve member 26 to the right to the position shown inFig. 3 to cause the refrigerating system to operate on the coolingcycle. When the shaft rotates in clockwise direction, the sleeve movesthe valve member 26 to the left for the heating cycle. A screw 35 isprovided to adjust the degree to which the sleeve 34 is clamped on theshaft 20 in order to adjust the degree of drag or slip.

The reversible cycle refrigerating system, which is illustrateddiagrammatically, may be incorporated in any suitable form of apparatus.It is particularly suited for a self-contained air conditioning unitadapted to be mounted in the window of a room or a unit adapted to beplaced in a room and connected outside with suitable ducts.

In accordance with the present invention, expansion means are providedwhich include two tubes 40 and 4| of considerable length and restrictedbore connected between the lower ends of the two coils l and II. Suchtubes are commonly referred to in the art as capillary tubes. In theembodiment shown in Fig. 1, the flow of refrigerant during the coolingcycle is indicated by solid line arrows. During this cycle of operation,the tube 40 serves as the expansion means and the tube 4| is madeinactive by a check valve 43 located near the end thereof that isconsidered the high-pressure or inlet end during the cooling cycle. Theflow of refrigerant during the heating cycle is indicated by the brokenline arrows. During the heating cycle the tube 4| serves as theexpansion means and the tube 40 is made inactive by a check valve 44located near the end thereof that is considered the high-pressure orinlet end thereof during the heating cycle.

The capillary tube 40 is arranged in heattransfer relation to theconduit 24 which is the suction line during the cooling cycle,preferably, by soldering the two together for a suitable length therebyproviding a heat exchanger 45 which permits counterflow heat-transferfrom the liquid refrigerant in the capillary tube 40 to the suction gasduring the cooling cycle. The capillary tube 4| is arranged inheat-transfer relation to the conduit 23 which is the suction lineduring the heating cycle, preferably, by soldering the two together fora suitable length thereby providing a heat exchanger 46 which permitsheat transfer from the liquid refrigerant in the cap illary tube 4| tothe suction gas during the heating cycle.

Provision is made to avoid flow of liquid refrigerant into the inactivecapillary tube during both the cooling and the heating cycle, to preventheat transfer from the hot compressed gaseous refrigerant to the liquidrefrigerant, since such heat transfer is a loss of cooling effort. Thisis accomplished by providing an inclined or uphill portion 41 ofcapillary tube that extends between the lower end of the coil l0 and theportion of the capillary tube 4| that is attached to the conduit 23.This inclined tube prevents liquid refrigerant from flowing from thecoil l0 into the inactive capillary tube 4| when the system is operatingon the cooling cycle. Any liquid refrigerant trapped in the inactivecapillary tube 4| between the check valve 43 and the coil H3 istransformed into highly superheated vapor by the heat from the hot gasin the high-pressure line 23 and this vapor is substantially static. Aninclined or uphill portion 48 of capillary tube is also provided betweenthe lower end of the coil II and the portion of the capillary tube 40that is attached to the conduit 24. This inclined or uphill tube 48prevents liquid refrigerant from flowing from th coil ll into theinactive capillary tube 40 when the system is operating on the heatingcycle. Any liquid refrigerant trapped in the inactive capillary tube 40between the check valve 44 and the coil II is transformed into highlysuperheated vapor by the heat from the hot gas in the high-pressure line24 and this vapor is substantially static.

In the embodiment shown in Fig. 2, check valves 43' and 44' are providednear the discharge or low-pressure ends of the capillary tubes 4| and40', respectively. With this arrangement, the inactive portions of thecapillary tubes are on the high-pressure sides of the check valves,instead of on the low-pressure sides, as with the arrangement shown inFig. 1. An inclined or uphill portion 41' of capillary tube connectsbetween the lower end of the coil H and that portion of the capillarytube 4| that is attached to the conduit 23 to prevent liquid refrigerantfrom flowing from the coil into the inactive capillary tube when thesystem is operating on the cooling cycle. Likewise, an inclined oruphill portion 48' of capillary tube connects the lower end of the coilI0 to that portion of the capillary tube 40' that is attached to theconduit 24 to prevent liquid refrigerant from flowing from the coil l0into the inactive capillary tube 40' when the system is operating on theheating cycle. In all other respects, this embodiment is the same andoperates in the same manner as the previous embodiment.

It will be understood that any desired length of capillary tube beyondthe heat exchanger portion may be provided at each end; also that anyAssume that it is desiredto cool the enclosure served by therefrigerating system illustrated in 'Fig. 1. Theswitch 3| is placed inthe position illustrated to provide the cooling cycle andthe switch 33is closed to connect the motor with the source of electric current. Theshaft 20 rotates in counterclockwise direction moving the valve member26 to the right, to the position illustrated in Fig. 3. The system nowoperates in the usual manner of a refrigerating system. Refrigerantvapor from the interior of the casing I8 is drawn through the motor andthe conduit I! to the compressor where its pressure is increased. Thecompressed refrigerant is conveyed through the conduit l8, theconnecting passage of the reversing valve l9 and the conduit 23 to theoutside air or condenser coil H. The condensed refrigerant flows throughthe capillary tube 40 wherein its pressure is reduced; It then flowsthrough the conditioned air coil or evaporator l0 wherein it extractsheat from the air which is circulated over the coil l0 and delivered tothe enclosure, the refrigerant being vaporized by the extracted heat.The; vaporized refrigerant then flows through the conduit 24, theconnecting passage of the reversing valve is and the conduit 22, and theaccumulator 23 to the interior of the casing I6 from which it isrecirculated.

During this cycle, liquid refrigerant trapped in the inactive capillarytube 4! is transformed into highly superheated vapor, and the inclinedor uphill portion 41 of the capillary tube prevents liquid refrigerantfrom flowing from the coil I0 into the tube 4|. This absence of flowprevents heat transfer from the. pressure line 23 to the liquidrefrigerant.

Referring to Fig. 2, the operation during the cooling cycle is the sameas that of the first embodiment except that the gaseous refrigerant inthe heat-exchanger portion of the inactive capillary tube is incommunication with the condenser and is therefore at high pressure. Thisembodiment has the advantage that, in the event of leakage through thecheck valve, the refrigerant leaking therethrough would be gaseousrefrigerant, thereby reducing the leakage of refrigerant measured byweight.

Assume that it is desired to heat the enclosure served by therefrigerating system illustrated in Fig. 1, the switch 3| is moved toplace the capacitor winding in the circuit including the line L2 and theswitch 33 is closed. The shaft 29 operates in clockwise directiondragging the sleeve 34 with it until the valve member 26 is moved to theleft. The connections are now reversed so that the compressed gas flowsthrough the conduit 24 to the conditioned air coil [0. As it flowsthrough the coil ill it gives up its superheat and latent heat to theair circulating over the coil and is thereby condensed. The heated airis delivered to the enclosure to maintain it at a comfortabletemperature. The condensed refrigerant flows through the successivetubes to the bottom of the coil ill from which it enters the capillarytube ll, 7

wherein its pressure is reduced. From the latter it enters the outsideair coil l I. As it flows through the latter, it absorbs heat from theoutside air flowing over the coil H and is thereby vaporized. Thevaporized refrigerant discharged from the upper end of the coil ll flowsthrough the conduit 23. the connecting passage of the reversing valveIS, the conduit 22 and the accumulator 23 to the interior of the casingl6. From the latter it is circulated through the motor, the conduit l1and the compressor I4 to the discharge conduit l8.

During this cycle, liquid refrigerant trapped in the inactive capillarytube 43 is converted into highly superheated vapor, and the inclinedportion of the capillary tube prevents liquid refrigerant from flowingfrom the coil Ii into the tube 40. This absence of flow in this tubeprevents heat transfer from the high-pressure line to the liquidrefrigerant.

The operation of the embodiment shown in Fig. 2 to heat the air withinthe enclosure is substantially the same as that for the embodiment shownin Fig. 1, except, that the gaseous refrigerant in the heat-exchangerportion of the inactive capillary tube is in communication with thecondenser and is therefore at high pressure.

In both embodiments of this invention, it will be noted that whenoperating on both the cooling and the heating cycle, the flow of gas inthe suction line is in a direction opposite to the flow of liquidrefrigerant in the capillary tube attachd thereto. This counterflow ofgas and liquid refrigerant permits the liquid refrigerant to giveup amaximum amount of heat to the suction gas. This transfer of heat fromthe liquid refrigerant to the suction gas increases the efficiency ofthe refrigerating system,

While I have shown my invention in several forms, it will'be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appendedclaims.

What I claim is:

1. In a reversible cycle refrigerating system for heating or cooling airfor an enclosure, the combination of a compressor, flrst and second heatexchangers, the second heat exchanger being arranged to heat or cool airfor the enclosure, first and second expansion devices connected betweensaid heat exchangers and serving to expand refrigerant from condensingpressure to evaporating pressure during the cooling cycle and theheating cycle, respectively, each of said expansion devices comprising apassage of considerable length and restricted flow area, and meansincluding valve mechanism and conduit portions for selectivelyconnecting the suction and discharge of said compressor to said firstand said second heat exchanger, respectively, for heating air for theenclosure, or to said second and said first heat exchanger,respectively, for cooling air for the enclosure, said conduit portionsbeing constructed and arranged to convey the expanded and vaporizedrefrigerant in counterflow heat transfer to the refrigerant in saidfirst expansion 'device during the cooling cycle and to the refrigerantin said second expansion device during the heating cycle.

2. In a reversible cycle refrigerating system for heating or cooling airfor an enclosure, the combination of a compressor, first and second heatexchangers, the second heat exchanger being arranged to heat or cool airfor the enclosure, first and second expansion devices connected betweensaid heat exchangers and serving to'expand refrigerant from condensingpressure to evaporating pressure during the cooling cycle and theheating cycle, respectively, each or said expansion devices comprising apassage of considerable length and restricted flow area, first andsecond conduits connected to said first and second heat exchangers,respectively, means including valve means for selectively connecting thesuction and discharge of said compressor to said first and secondconduits, respectively, for operation of the system to heat air for theenclosure or to said second and said first conduit, respectively, foroperation of the system to cool air for the enclosure, said first andsecond expansion devices being arranged in heat-transfer relation tosaid second and said first conduits, respectively, for a considerablelength thereof in such manner that during the cooling cycle the liquidrefrigerant in said first expansion device flows in counterfiow heatrelation to the gaseous refrigerant in said second conduit and duringthe heating cycle the liquid refrigerant in said second expansion devicefiows in counterflow heat relation to the gaseous refrigerant in saidfirst conduit.

3. In a reversible cycle refrigerating system for heating or cooling airfor an enclosure, the

' combination of a compressor, first and second heat exchangers, firstand second conduits connected to said compressor and to said first andsecond heat exchangers, respectively, said second heat exchanger beingarranged to heat or cool air for the enclosure, first and secondcapillary tubes connected in parallel between said heat exchangers andserving to expand refrigerant from condensing pressure to evaporatingpressure during the cooling cycle and the heating cycle, respectively, acheck valve arranged in each of said capillary tubes, said check valvesbeing arranged so that during the cooling cycle said secondcapilla ytube is made inactive by its check valve and during the heating cyclesaid first capillary tube is made inactive by its check valve, and valvemeans for selectively connecting the suction and discharge of saidcompressor to said first and said second conduits, respectively, foroperation of the system to heat air for the enclosure or to said secondand said first conduits, respectively, for operation of the system tocool air for the enclosure.

4. In a reversible cycle refrigerating system for heatingor cooling airfor an enclosure, the combination of a compressor, first and second heatexchangers, first and second conduits connected to'said compressor andto said first and second heat exchangers, respectively, the second heatexchanger being arranged to heat or cool air for the enclosure, firstand second capillary tubes connected between said heat exchangers, saidfirst capillary tube being arranged in heat-transfer relation to saidsecond conduit for a considerable length thereof and adapted to expandreirigerant from condensing pressure to evaporat ing pressure during thecooling cycle, said second capillary tube being arranged inheat-transfer relation to said first conduit for a considerable lengththereof and adapted to expand refrigerant from condensing pressure toevaporating pressure during the heating cycle, means for rendering saidsecond capillary tube inactive and maintaining absence of fiow thereintoduring the cooling cycle, means for rendering said first capillary tubeinactive and maintaining absence of flow thereinto during th heatingcycle, and valve means for selectively connecting the suction anddischarge of said compressor to said first and said second conduits,respectively, for operation of the systemto heat the air for theenclosure or to said second and said first heat exchanger, respectively,for operation of the system to cool the air for the enclosure.

5. .In a reversible cycle refrigerating system for heating or coolingair for an enclosure, the combination of a compressor, first and secondheat exchangers, first and second conduits connecting said compressor tosaid heat exchangers, the

second heat exchanger being arranged to heat or cool air for theenclosure, first and second capillary tubes connected between said heatexchangers, said first and second capillary tubes being arranged for aconsiderable length thereof in heat-transfer relation to said second andsaid first conduits, respectively, said first capillary tube serving toexpand refrigerant from condensing pressure to evaporating pressureduring the cooling cycle, a check valve arranged in said secondcapillary tube to render the same inactive during the cooling cycle,that no on of said second capillary tube that is in heat-transferrelation to said first conduit being on the'low pressure side of saidcheck valve during the cooling cycle, said first conduit being thehigh-pressure conduit during this cycle of operation, the heat from therefrigerant gas flowing through said first conduit serving to transformliquid refrigerant trapped insaid second capillary tube into superheatedgas some of which remain static in said second capillary tube, saidsecond capillary tube serving to expand refrigerant from condensingpressure to evaporating pressure during the heating cycle, a check valvearranged in said first capillary tube to render the same inactive duringthis cycle of operation, that portion or said first capillar tube thatis in heat-transfer relation to said second conduit being on the lowpressure side of said check valve during the heating cycle, said secondconduit being the high pressure conduit during the heating cycle, theheat from the refrigerant gas flowing in said second conduit being suchthat it transforms liquid refrigerant trapped in the first capillaryjtube into superheated vapor some of which remains static in this tube,and valve means for selectively connecting the suction and discharge ofsaid compressor to said first and said second conduits, respectively,for operation of the system to heat air for the enclosure or to saidsecond and said first conduits, respectively, for operation of thesystem to cool air for the enclosure.

6. In a reversible cycle refrigerating system for heating or cooling airfor an enclosure, the combination of a compressor, first and second heatexchangers, first and second conduits connecting said compressor to saidheat exchangers, the second heat exchanger being arranged to heat orcool air for the enclosure, first and second capillary tubes connectedbetween said heat exchangers and serving to expand liquid refrigerantfrom condensing pressure to evaporating pressure during the coolingcycle and the heating cycle, respectively, said first and secondcapillary tubes being arranged for a considerable length thereof inheat-transfer relationship to said second and said first conduits,respectively, a check valve arranged in said second capillary tube torender the same inactive during the cooling cycle, said check valvebeing so positioned that the portion of said second capillary tube thatis in heat-transfer relation to said first conduit is on thehigh-pressure side of said check valve during the cooling cycle, a.check valve arranged in said first capillary tube to render the sameinactive during the heating cycle, said check valve being so positionedthat the portion or the first capillary tube that is in heat-transferrelation to said second conduit is on the high-pressure side of saidcheck valve during the heating cycle, and valve means for selectivelyconnecting the suction and discharge of said compressor to said firstand said second conduits, respectively, for operation of the system toheat air for the enclosure or to said second and said first conduits,respectively, for operation oi! the system to cool air for theenclosure.

7. In a reversible cycle refrigerating system for heating or cooling'air for an enclosure, the combination oi! a compressor, first andsecond heat exchangers, the second heat exchanger being arranged to heator cool air for the enclosure, first and second capillary tubesconnected between said heat exchangers and serving to expand refrigerantfrom condensing pressure to evaporating pressure during the coolingcycle and so the heating cycle, respectively, check valves arranged torender the second capillary tube inactive during the cooling cycle andthe first capillary tube inactive during the heating cycle, meansincluding an inclined portion of capillary tube to prevent liquidrefrigerant from flowing from said second heat exchanger into saidsecond capillary tube during the cooling cycle, means including aninclined portion of capillary tube to prevent liquid refrigerant fromflowing from said said first heatexchanger into said first capillarytube during the heating cycle,. and valve means for selectivelyconnecting the suction and discharge or said compressor to said firstand s'aid 15 second heat exchangers, respectively, for heating airforthe enclosure or to said second and said first conduit, respectively,for cooling air for the enclosure.

RUDOLPH J. EI SINGER.

